Thanks all for comments. I will try to briefly deal with a few of them:
Interesting the increase in the percentage divorced from 5.86% to 6.47% in just 5 years.
It could be connected to the median age going up in those 5 years. It is surprising, though.
A relevant question is, "What percentage of divorced JWs were divorced BEFORE they became Witnesses?"
That is a good question. I have no easy way of separating that out. However, "divorced" means divorced and not in a new relationship on census night, which should limit such numbers. Also, you could ask the same question of any of the other religions, including SDA and Mormons who appear to be having more recruitment success.
And it could be that many JWs divorce non-JW partners.
Yes that would be a significant proportion. However, I think JW's divorcing non-JW's is an appropriate inclusion and I wouldn't separate them out if I could.
Also..... What about those that have remarried?
They are counted as "married", as pointed out by Darkspilver. Yes, the number of people who have ever divorced would be way higher. As I said above, "Divorced" means divorced and not in a new relationship on census night.
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These good comments show the limitations of the use of the data from the census, when trying to compare divorce statistics between different religions. However, the limitations broadly apply to each of the religions listed, not just JW. If you accept the data for what it is, I think it is still valid to conclude that (to repeat myself above) divorce and separation rates for JW's are pretty typical of what you would find in "Christendom".